Apart from application of heat, extensive cursing, molegrips and a big hammer, try:
Acetone and ATF (automatic trans. fluid), 50/50 mix, in a spray bottle.
Appears to work better than WD-40 (which is not really a penetrating oil anyway), or PB Blaster, or Liquid Wrench, or Kano-Kroil.
This came from a 2007 test article in the magazine "Machinist's Workshop."
2006 XB12Ss..... 1998 S1W..... 1996 S2T
We do not need the help of our friends so much as confidence that they will help us when we need it. –Epicurus